Physics 2 Test chapters 12 &13 Flashcards
When the crystals are defective, the entire image is destroyed with this type of transducer
Single crystal transducer.
Mechanical transducer
Pg 167
What’s the typical value for the electrical signal delay in a phased array transducer?
4-10 nanoseconds
notes and p. 172
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Which transducer creates a beam that is focused in all planes and at all depths?
annular phased array
quizlet???
What is the advantage of using a 1 1/2 dimensional array transducer?
Addition of slice thickness/elevational resolution.
Pg188
What type of resolutions are we considering with a 1 1/2 dimensional array transducer?
Slice thickness and
Elevational resolution
Pg 188
What is the image shape of a vector array transducer?
Trapezoidal
Pg 187
Which transducer has active elements arranged in a straight line?
Linear
Pg 168
Which transducer has active elements arranged in circular rings?
Annular
Pg 168
Which transducer has active elements arranged in an arched or bowed matter?
Convex
Pg168
Phased array always means what?
Adjustable or multi-focused
Pg 170
Linear switch transducer has what type of steering technique?
Also called linear sequential. Has electronic steering.
Pg 187
What type of probe has dropout lines of image information from top to bottom?
Linear and convex
Pg187
Horizontal or side to side dropout occurs in which transducer type when crystals are bad?
Annular phased array.
Pg187
Which transducer is designed to be mechanically steered and fixed with single focus?
Mechanical
Pg187
What is dynamic aperture?
“transmit hole” or “listening hole”
makes sound beam narrow over a greater range of depths
improves lateral resolution
Pg194
What is the ultrasound machine that can display real time images and Doppler?
Duplex
pg 313
I just have a note I wrote in my book on pg 183 next to the bottom pic.
The ability to accurately to locate moving structures at any time is what kind of resolution?
Temporal resolution
Pg 198
What will decrease temporal resolution?
Deep imaging
Low frame rate
Pg 200
Real-time imaging could be referred to as…?
Ultrasound “movie”
Pg 197
What determines temporal resolution?
Frame rate
Pg198
What are the factors that limit frame rate?
speed of sound in the medium
Imaging depth
Pg 198
What will affect the pulses in a single image?
Number of focal points
Sector size
Line density
Pg 201
If we double imaging depth, what happens to frame rate?
Frame rate is halved
Pg 210
Imaging to greater depth of view requires what?
Long go-return time Longer Tframe Lower frame rate Lower temporal resolution Pg 200
What will degrade temporal resolution?
Deeper imaging Multiple focal points Wide sector High line density Pg 209
What is the sector size that will use the fewest pulses?
The narrowest sector size
p. 204
The sonographer increases line density from 1 line to 3 lines, what will be the consequence of this action?
Temporal resolution decreases
p. 211
If the frame rate is 50 Hz, how long does it take to create a frame?
1/50 sec
p. 214 (#23 is an example of this)
Lateral resolution improves with what?
Multi-focus
p 209
Low line density creates what?
widely spaced lines fewer pulses per frame shorter T frame higher frame rate high temporal resolution poor spatial resolution p. 207 (yellow box)
What creates an image with poor movie quality but high image quality?
Poor temporal resolution
Low frame rate
Pg 208
Increasing the line density degrades _____ and improves _____.
Degrades temporal resolution and improves spatial resolution
p. 207
A critical factor in determining frame rate, line density and imaging depth is?
Time
pg 213
If imaging depth is 15 cm and there’s 100 lines…
When frame is made quickly…how many Frames created per second?
100 frames per second
p. 213
???
Using a phased array ultrasound system, if you turn off the multi-focus feature what will most likely be a consequence of this action?
Temporal resolution increases
pg 211
Which of following is consistent with increased or improved spatial resolution?
High line density
p. 207
When a frame is made quickly, how many frames are created per second?
~
When you have 1 frame created in 1/100 second, what is the frame rate?
100 per second or 100 Hz
p. 213
What are the different shapes of images for all different probes?
Mechanical - sector Linear sequential - rectangle Phased array - sector Annular phased - sector Convex - blunted sector Vector - trapezoidal
Know about steering to the right and steering to the left
~
What is apodization?
Stronger electrical signals are used to excite inner crystals, and progressively weaker spikes excite the outer crystals then lobes are diminished
p. 193
Focused and unfocused
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What are side lobes and grating lobes?
Side lobes: sound beams created by single element transducers and are additional areas of sound energy extend outside of the main beam in the far zone
Grating lobes: created by array transducers, the extra off-axis sound beams are undesirable because they degrade lateral resolution, reduce image quality, and create artifacts
p. 192
